Add missing NOTICE files.

Copy the NOTICE file from external/sonivox to external/sonivox/arm-wt-22k,
where it will be picked up by the build system.

Change-Id: Ieb1c6bbb510b6cc9c375c6250b70d9413aa511a7
diff --git a/arm-wt-22k/NOTICE b/arm-wt-22k/NOTICE
new file mode 100644
index 0000000..1f00f30
--- /dev/null
+++ b/arm-wt-22k/NOTICE
@@ -0,0 +1,14 @@
+Copyright (c) 2004-2006 Sonic Network Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+